US6751539B2 - Vehicle steering control system - Google Patents

Vehicle steering control system Download PDF

Info

Publication number
US6751539B2
US6751539B2 US10/241,781 US24178102A US6751539B2 US 6751539 B2 US6751539 B2 US 6751539B2 US 24178102 A US24178102 A US 24178102A US 6751539 B2 US6751539 B2 US 6751539B2
Authority
US
United States
Prior art keywords
steering
reaction force
steering reaction
actuator
road surface
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US10/241,781
Other versions
US20030055545A1 (en
Inventor
Kenya Uenuma
Hiroshi Mouri
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nissan Motor Co Ltd
Original Assignee
Nissan Motor Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nissan Motor Co Ltd filed Critical Nissan Motor Co Ltd
Assigned to NISSAN MOTOR CO., LTD. reassignment NISSAN MOTOR CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MOURI, HIROSHI, UENUMA, KENYA
Publication of US20030055545A1 publication Critical patent/US20030055545A1/en
Application granted granted Critical
Publication of US6751539B2 publication Critical patent/US6751539B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
    • B62D6/008—Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications

Definitions

  • the present invention relates to vehicle steering control systems, and more particular, to the systems of a so-called “steer-by-wire type” wherein a first steering unit that is handled by a driver and a second steering unit that steers steered road wheels are not connected through a linkage mechanism, that is, the steered road wheels are steered by a powered actuator in accordance with an information signal issued from a sensor associated with a steering wheel.
  • One steering control system of the steer-by-wire type is shown in Japanese Laid-open Patent Application (Tokkaihei) 11-78947.
  • this system for steering the steered road wheels, there are employed an electric motor that produces a power to steer the steered road wheels, sensing devices that sense an angle of rotation of the steering wheel and a steering torque of the same and a steering reaction force generating device that imparts a steering resistance to the operational force of the steering wheel.
  • a driver when driving a motor vehicle, a driver has to handle various control devices suitably in accordance with the existing conditions of and around the vehicle with the aid of tactile information as well as visual information.
  • a steering reaction force viz., a counterforce felt by the driver through the steering wheel when he or she turns the steering wheel
  • the steering reaction force is passively transmitted to the driver through the linkage mechanism.
  • a steering mechanism of steer-by-wire type wherein there is no linkage mechanism between the steering wheel and the steered road wheels, it is necessary to provide a device that positively provides the steering wheel with a suitable steering reaction force.
  • the steering reaction force is readily derived or calculated by using information signals issued from a yaw rate sensor and a lateral acceleration sensor that are mounted on the vehicle.
  • information on a roughness degree of road surface it is very difficult to derive or calculate the steering reaction force because the behavior of the motor vehicle caused by such roughness of road surface is quite small.
  • a torque sensor is mounted on the second steering unit to directly derive or calculate a disturbance originating from the road surface.
  • the arrangement of the torque sensor proposed by this publication tends to reduce the rigidity of the second steering unit because of the nature of the actually employed torque sensor. That is, usage of the torque sensor means that a shaft portion of the second steering unit has a diametrically reduced part which is subjected to a torsional movement when applied with a certain torque. The diametrically reduced part causes the reduced rigidity of the second steering unit.
  • Japanese Laid-open Patent Application (Tokkai) 2000-128002 proposes usage of a position sensor which senses a stroke position of a rack shaft of the second steering unit.
  • the position sensor mounted on the second steering unit has no influence on the rigidity of the second steering unit.
  • a linear approximate equation is used for calculating the steering reaction force.
  • satisfied calculation of the steering reaction force has not been carried out because of contradiction of usage of such “linear” equation in the field of steering system which has “nonlinear” characteristics.
  • a vehicle steering control system for use with a steering mechanism of steer-by-wire type, the steering mechanism including a first steering unit that is handed by a driver and a second steering unit that steers steered road wheels with the aid of a steering actuator, the first and second steering units being mechanically unconnected, the vehicle steering control system comprising a steering reaction force actuator that generates a steering reaction force that is to be applied to the first steering unit in accordance with a steered movement of the steered road wheels; an input detecting section that detects an input applied to the steering actuator; an output detecting section that detects an output issued from the steering actuator; a road surface disturbance estimating section that estimates a disturbance of road surface based on both the detected input and output of the steering actuator; a steering reaction force calculating section that, based on the estimated disturbance of road surface, calculates a steering reaction force which is to be applied to the first steering unit; and a steering reaction force control section that instructs the steering reaction force actuator to generate a
  • a vehicle steering control system for use with a steering mechanism of steer-by-wire type, the steering mechanism including a first steering unit that is handed by a driver and a second steering unit that steers steered road wheels with the aid of a steering actuator, the first and second steering units being mechanically unconnected, the vehicle steering control system comprising: a steering reaction force generating means that generates a steering reaction force that is to be applied to the first steering unit in accordance with a steered movement of the steered road wheels; an input detecting means that detects an input applied to the steering actuator; an output detecting means that detects an output issued from the steering actuator; a road surface disturbance estimating means that estimates a disturbance of road surface based on both the detected input and output of the steering actuator; a steering reaction force calculating means that, based on the estimated disturbance of road surface, calculates a steering reaction force which is to be applied to the first steering unit; and a steering reaction force control means that instructs the steering reaction force actuator to
  • a method of controlling a vehicle steering control system for use with a steering mechanism of steer-by-wire type the steering mechanism including a first steering unit that is handed by a driver and a second steering unit that steers steered road wheels without a direct aid of the first steering unit, a steering actuator that actuates the second steering unit and a steering reaction force actuator that applies a steering reaction force to the first steering unit in accordance with a steered movement of the steered road wheels, the method comprising detecting an input applied to the steering actuator; detecting an output issued from the steering actuator; estimating a disturbance of road surface based on both the detected input and output of the steering actuator; calculating, based on the estimated disturbance of road surface, a steering reaction force which is to be applied to the first steering unit; and instructing the steering reaction force actuator to generate a steering reaction force in accordance with the calculated steering reaction force.
  • FIG. 1 is a schematic diagram of an overall structure of a vehicle steering control system of a first embodiment of the present invention
  • FIG. 2 is a block diagram of a steering motor employed in the first embodiment, under a normal condition
  • FIG. 3 is a block diagram of the steering motor employed in the first embodiment, under a condition wherein a certain disturbance originating from a roughness of road surface is applied to the steering motor;
  • FIG. 4 is a block diagram showing the concept of the first embodiment of the present invention.
  • FIG. 5 is a view similar to FIG. 4, but showing the concept of a second embodiment of the present invention.
  • FIG. 6 is a view similar to FIG. 4, but showing the concept of a third embodiment of the present invention.
  • FIG. 1 there is schematically shown a vehicle steering control system 100 of a first embodiment of the present invention, which is practically applied to a front wheel steering system installed in a motor vehicle.
  • 1 is a steering wheel
  • 2 is a steering reaction force actuator
  • 7 is a steering motor drive section
  • 9 is a steering motor
  • 10 is a steering gear unit
  • 11 a and 11 b are tie rods
  • 12 is an encoder
  • 14 is a road surface disturbance estimation section
  • 18 is a road surface disturbance based steering reaction force calculating section (or a second steering reaction force calculating section)
  • 21 is a vehicle behavior based steering reaction force calculating section (or a first steering reaction force calculating section)
  • 22 is an instruction current calculating section
  • 28 is a final steering reaction force calculating section.
  • the steering wheel 1 is a device that is handled by a driver. That is, when steering wheel 1 is handed by the driver, a torque sensor 2 a installed in steering reaction force actuator 2 detects a steering torque “T H ” and at the same time, an encoder 2 b in the actuator 2 detects a steering angle “ ⁇ H ” by which steering wheel 1 has been steered by the driver.
  • steering motor drive section 7 there are inputted, in addition to information signals on the above-mentioned steering torque “TH” and steering angle “ ⁇ H ”, information signals on a yaw rate “y” of the vehicle detected by a yaw rate gyro or the like, a lateral acceleration “ ⁇ ” of the vehicle detected by a lateral acceleration sensor or the like, and other known information such as a vehicle speed “Vs” and the like. Based on these information signals inputted, steering motor drive section 7 calculates an instruction current “i” which is applied to steering motor 9 . As shown, the instruction current “i” is applied to road surface disturbance estimation section 14 also.
  • Output rotation of steering motor 9 is transmitted to steering gear unit 10 , which is of a rack-and-pinion type, and thus, steered road wheels (not shown) are actuated by steering gear unit 10 through tie rods 11 a and 11 b.
  • the encoder 12 is arranged concentric with an output shaft of steering motor 9 to monitor or detect a rotation angle “ ⁇ ” of the output shaft of steering motor 9 .
  • An information signal on rotation angle “ ⁇ ” is fed back to steering motor drive section 7 to force the section 7 to carry out a servo control on the steered angle.
  • the information signal on the rotation angle “ ⁇ ” is fed to road surface disturbance estimation section 14 also.
  • road surface disturbance estimation section 14 there are inputted the information signal on the instruction current “i” applied to the steering motor 9 and that on the rotation angle “ ⁇ ” of the output shaft of steering motor 9 . Based on these information signals “i” and “ ⁇ ”, the road surface disturbance estimation section 14 calculates an estimated disturbance torque “ ⁇ circumflex over (T) ⁇ d” which would be caused by disturbance of road surface.
  • the road surface disturbance estimation section 14 comprises generally a first block 15 into which the information signal “i” is inputted and a second block 16 into which the information signal “ ⁇ ” is inputted.
  • a torque “t 1 ” that should be generated is estimated.
  • t 1 K T ⁇ ⁇ 2 s 2 + 2 ⁇ ⁇ ⁇ ⁇ s + ⁇ 2 ( 1 )
  • t 2 J ⁇ ⁇ ⁇ 2 ⁇ s 2 s 2 + 2 ⁇ ⁇ ⁇ ⁇ s + ⁇ 2 ( 2 )
  • the second steering reaction force calculating section 21 Into the second steering reaction force calculating section 21 , there are inputted information signals on a vehicle running condition, that is, on steering torque “T H ”, steering angle “ ⁇ H ”, yaw rate “y” of the vehicle, lateral acceleration “ ⁇ ” of the vehicle, vehicle speed “Vs” and rotation angle “ ⁇ ”. Based on these information signals, the second steering reaction force calculating section 21 calculates a steering reaction force “T 2 ” which would be transmitted to the driver through the steering wheel 1 .
  • a suitable gain is applied to the estimated disturbance torque “ ⁇ circumflex over (T) ⁇ d” to calculate a steering reaction force “T 1 ” which would be caused by the disturbance of road surface.
  • a subtraction “T 2 ⁇ T 1 ” is carried out to obtain a final steering reaction force (T 2 ⁇ T 1 ).
  • the final steering reaction force (T 2 ⁇ T 1 ) is divided by a torque constant “K TH ” of steering reaction force actuator 2 to obtain an instruction current “i H ” which is fed to the actuator 2 .
  • FIG. 2 is a block diagram schematically showing the steering motor 9 based on an equation of motion of the motor 9 .
  • a torque “T” is obtained, and by dividing the torque “T” by an inertia “J” of motor 9 , a rotation speed “ ⁇ umlaut over ( ⁇ ) ⁇ ” of motor 9 is obtained.
  • a rotation angle “ ⁇ ” of the output shaft of the motor 9 is obtained.
  • the steering motor 9 can be schematically shown by FIG. 3 in which a disturbance torque “T d ” is led to a middle of the block diagram of FIG. 2 . Due to presence of the disturbance torque “T d ”, it tends to occur that steering motor 9 exhibits excess or deficiency of output upon receiving the instruction current “i”. In general, in controlling steering motor 9 , instruction and output of the motor 9 are evenly carried out by feeding back the rotation angle “ ⁇ ” to the control.
  • FIG. 4 is a block diagram showing both steering motor 9 and road surface disturbance estimation section 14 .
  • the disturbance torque “Td” is estimated. That is, the instruction current “i” led to steering motor 9 is fed to the first block 15 . With this, the first block 15 estimates a torque “t 1 ” in the form of transfer function, that should be generated. While, the information on rotation angle “ ⁇ ” is led to the second block 16 . With this, the second block 16 estimates a torque “t 2 ” that would be instructed. By calculating a difference between the generated torque and the instructed torque, the estimated disturbance torque “ ⁇ circumflex over (T) ⁇ d” is obtained.
  • a suitable gain “G” is kept applied to the estimated disturbance torque “ ⁇ circumflex over (T) ⁇ d” to calculate a steering reaction force “T 1 ” which would be caused by a disturbance of road surface.
  • a steering reaction force “T 2 ” is calculated based on the vehicle running condition.
  • a subtraction “T 2 ⁇ T 1 ” is carried out to obtain a final steering reaction force (T 2 ⁇ T 1 ).
  • the instruction current calculating section 22 the final steering reaction force (T 2 ⁇ T 1 ) is divided by a torque constant “K TH ” of steering reaction force actuator 2 to obtain an instruction current “i H ” which is fed to the actuator 2 .
  • the disturbance torque “T d ” caused by a disturbance of road surface is estimated, and based on the estimated disturbance torque “T d ”, the steering reaction force “T 1 ” that is to be applied to the steering wheel 1 is calculated.
  • the estimation of disturbance of road surface is made by only the encoder 12 that is needed for controlling the steering motor 9 . Accordingly, lowering in rigidity and that in reliability of the vehicle steering control system can be avoided.
  • the steering reaction force calculating part of the system 100 comprises the first steering reaction force calculating section 18 that, based on the estimated disturbance torque “ ⁇ circumflex over (T) ⁇ d” from road surface disturbance estimation section 14 , calculates the steering reaction force “T 1 ” which would be caused by the disturbance of road surface, the second steering reaction force calculating section 21 that, based on various information on a marked behavior of the vehicle, calculates the steering reaction force “T 2 ” which should be transmitted to the driver and the final steering reaction force calculating section 28 that, based on both the calculated two reaction forces “T 1 ” and “T 2 ”, calculates the final steering reaction force (T 2 ⁇ T 1 ).
  • the final steering reaction force (T 2 ⁇ T 1 ) thus calculated reflects both a reaction force based on the marked behavior of the vehicle and that based on the road surface disturbance “T d ”, and thus, a precise steering reaction force can be transmitted to the driver.
  • FIG. 5 there is schematically shown the concept of a second embodiment 200 of the present invention.
  • the second embodiment 200 is substantially the same as the above-mentioned first embodiment 100 except that in the second embodiment 200 , the information on rotation angle “ ⁇ ” of the output shaft of steering motor 9 is 10 treated by a first order lag filter 27 before being led into second block 16 of road surface disturbance estimation section 14 . That is, due to treatment by the filter 27 , information signal “ ⁇ ” is changed to an information signal “ ⁇ ′”, as shown.
  • equation “a/(s+a)” is employed wherein “a” is a filter constant.
  • steering motor 9 produces an information representing the rotation angle “ ⁇ ”.
  • the behavior of the vehicle caused by the steering action occurs somewhat later, so that the vehicle steering control system of the above-mentioned first embodiment 100 may fail to calculate the steering reaction force based on the vehicle running condition and the result provided by road surface disturbance estimation section 14 .
  • satisfied information is not transmitted to the vehicle driver.
  • usage of first order lag filter 27 enables a delayed input of information on rotation angle “ ⁇ ” into second block 16 of road surface disturbance estimation section 14 . That is, in the second embodiment 200, in the early period of the steering action, the disturbance caused by the roughness of road surface is estimated relatively large. However, practically, the vehicle driver can feel a much actual steering reaction force, and thus, the steerability of the vehicle is improved.
  • FIG. 6 there is schematically shown the concept of a third embodiment 300 of the present invention.
  • the third embodiment 300 is substantially the same as the above-mentioned first embodiment 100 except that in the third embodiment 300, the estimated disturbance torque “ ⁇ circumflex over (T) ⁇ d” is treated by a second order lag filter 29 before being led into first steering reaction force calculating section 18 (see FIG. 1 ). That is, due to treatment by the filter 29 , information “ ⁇ circumflex over (T) ⁇ d” is changed to an information “ ⁇ circumflex over (T) ⁇ d′”, as shown.
  • T ⁇ ⁇ d ′ ⁇ 0 2 s 2 + 2 ⁇ ⁇ 0 ⁇ ⁇ 0 ⁇ ⁇ s + ⁇ 0 2 ( 3 )
  • the frequency characteristic of the estimated disturbance torque can be suitably controlled. Specifically, in a high frequency zone, the gain of the estimated disturbance torque becomes small. Thus, when the vehicle steering control system 300 is practically used, an unnecessary marked vibration of a steering wheel, which would be generated when the vehicle is running on a bad road, is reduced. That is, the driver can receive only the information which is actually needed by the steering control.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)
  • Power Steering Mechanism (AREA)

Abstract

In a steering mechanism of steer-by-wire type which includes a first steering unit that is handled by a driver and a second steering unit that steers steered road wheels with the aid of a steering motor, there is employed a control system which input and output detecting sections that detect input and output of the steering motor, a road surface disturbance estimating section that estimates a disturbance of road surface based on both the detected input and output of the steering motor, and a steering reaction force calculating section that, based on the estimated disturbance of road surface, calculates a steering reaction force that is to be applied to a steering wheel of the first steering unit.

Description

BACKGROUND OF INVENTION
1. Field of Invention
The present invention relates to vehicle steering control systems, and more particular, to the systems of a so-called “steer-by-wire type” wherein a first steering unit that is handled by a driver and a second steering unit that steers steered road wheels are not connected through a linkage mechanism, that is, the steered road wheels are steered by a powered actuator in accordance with an information signal issued from a sensor associated with a steering wheel.
2. Description of Related Art
One steering control system of the steer-by-wire type is shown in Japanese Laid-open Patent Application (Tokkaihei) 11-78947. In this system, for steering the steered road wheels, there are employed an electric motor that produces a power to steer the steered road wheels, sensing devices that sense an angle of rotation of the steering wheel and a steering torque of the same and a steering reaction force generating device that imparts a steering resistance to the operational force of the steering wheel.
In general, when driving a motor vehicle, a driver has to handle various control devices suitably in accordance with the existing conditions of and around the vehicle with the aid of tactile information as well as visual information. Particularly, when handling a steering wheel, a steering reaction force (viz., a counterforce felt by the driver through the steering wheel when he or she turns the steering wheel) constitutes an important information that reliably represents a road surface condition and a vehicle running condition.
In a steering device of known linkage type wherein the steering wheel (namely, first steering unit) is connected to the steered road wheels (namely, second steering unit) through a linkage mechanism, the steering reaction force is passively transmitted to the driver through the linkage mechanism. While, in a steering mechanism of steer-by-wire type wherein there is no linkage mechanism between the steering wheel and the steered road wheels, it is necessary to provide a device that positively provides the steering wheel with a suitable steering reaction force.
When, like in corner turnings, a motor vehicle shows a relatively marked behavior, the steering reaction force is readily derived or calculated by using information signals issued from a yaw rate sensor and a lateral acceleration sensor that are mounted on the vehicle. However, regarding information on a roughness degree of road surface, it is very difficult to derive or calculate the steering reaction force because the behavior of the motor vehicle caused by such roughness of road surface is quite small.
In the steering control system of the above-mentioned publication 11-78947, a torque sensor is mounted on the second steering unit to directly derive or calculate a disturbance originating from the road surface. The arrangement of the torque sensor proposed by this publication however tends to reduce the rigidity of the second steering unit because of the nature of the actually employed torque sensor. That is, usage of the torque sensor means that a shaft portion of the second steering unit has a diametrically reduced part which is subjected to a torsional movement when applied with a certain torque. The diametrically reduced part causes the reduced rigidity of the second steering unit. In view of this, Japanese Laid-open Patent Application (Tokkai) 2000-128002 proposes usage of a position sensor which senses a stroke position of a rack shaft of the second steering unit. In this case, the position sensor mounted on the second steering unit has no influence on the rigidity of the second steering unit. Based on an information signal from the position sensor, a linear approximate equation is used for calculating the steering reaction force. However, even in this measure, satisfied calculation of the steering reaction force has not been carried out because of contradiction of usage of such “linear” equation in the field of steering system which has “nonlinear” characteristics.
SUMMARY OF INVENTION
It is therefore an object of the present invention to provide a vehicle steering control system which, without the aid of an additional sensor, can provide an accurate information on a roughness degree of road surface even when the roughness degree is small to such a degree as not induce a marked behavior of the associated motor vehicle.
According to a first aspect of the present invention, there is provided a vehicle steering control system for use with a steering mechanism of steer-by-wire type, the steering mechanism including a first steering unit that is handed by a driver and a second steering unit that steers steered road wheels with the aid of a steering actuator, the first and second steering units being mechanically unconnected, the vehicle steering control system comprising a steering reaction force actuator that generates a steering reaction force that is to be applied to the first steering unit in accordance with a steered movement of the steered road wheels; an input detecting section that detects an input applied to the steering actuator; an output detecting section that detects an output issued from the steering actuator; a road surface disturbance estimating section that estimates a disturbance of road surface based on both the detected input and output of the steering actuator; a steering reaction force calculating section that, based on the estimated disturbance of road surface, calculates a steering reaction force which is to be applied to the first steering unit; and a steering reaction force control section that instructs the steering reaction force actuator to generate a steering reaction force in accordance with the calculated steering reaction force.
According to a second aspect of the present invention, there is provided a vehicle steering control system for use with a steering mechanism of steer-by-wire type, the steering mechanism including a first steering unit that is handed by a driver and a second steering unit that steers steered road wheels with the aid of a steering actuator, the first and second steering units being mechanically unconnected, the vehicle steering control system comprising: a steering reaction force generating means that generates a steering reaction force that is to be applied to the first steering unit in accordance with a steered movement of the steered road wheels; an input detecting means that detects an input applied to the steering actuator; an output detecting means that detects an output issued from the steering actuator; a road surface disturbance estimating means that estimates a disturbance of road surface based on both the detected input and output of the steering actuator; a steering reaction force calculating means that, based on the estimated disturbance of road surface, calculates a steering reaction force which is to be applied to the first steering unit; and a steering reaction force control means that instructs the steering reaction force actuator to generate a steering reaction force in accordance with the calculated steering reaction force.
According to a third aspect of the present invention, there is provided a method of controlling a vehicle steering control system for use with a steering mechanism of steer-by-wire type, the steering mechanism including a first steering unit that is handed by a driver and a second steering unit that steers steered road wheels without a direct aid of the first steering unit, a steering actuator that actuates the second steering unit and a steering reaction force actuator that applies a steering reaction force to the first steering unit in accordance with a steered movement of the steered road wheels, the method comprising detecting an input applied to the steering actuator; detecting an output issued from the steering actuator; estimating a disturbance of road surface based on both the detected input and output of the steering actuator; calculating, based on the estimated disturbance of road surface, a steering reaction force which is to be applied to the first steering unit; and instructing the steering reaction force actuator to generate a steering reaction force in accordance with the calculated steering reaction force.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic diagram of an overall structure of a vehicle steering control system of a first embodiment of the present invention;
FIG. 2 is a block diagram of a steering motor employed in the first embodiment, under a normal condition;
FIG. 3 is a block diagram of the steering motor employed in the first embodiment, under a condition wherein a certain disturbance originating from a roughness of road surface is applied to the steering motor;
FIG. 4 is a block diagram showing the concept of the first embodiment of the present invention;
FIG. 5 is a view similar to FIG. 4, but showing the concept of a second embodiment of the present invention;
FIG. 6 is a view similar to FIG. 4, but showing the concept of a third embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
Referring to FIG. 1, there is schematically shown a vehicle steering control system 100 of a first embodiment of the present invention, which is practically applied to a front wheel steering system installed in a motor vehicle.
In the drawing, denoted by numeral 1 is a steering wheel, 2 is a steering reaction force actuator, 7 is a steering motor drive section, 9 is a steering motor, 10 is a steering gear unit, 11 a and 11 b are tie rods, 12 is an encoder, 14 is a road surface disturbance estimation section, 18 is a road surface disturbance based steering reaction force calculating section (or a second steering reaction force calculating section), 21 is a vehicle behavior based steering reaction force calculating section (or a first steering reaction force calculating section), 22 is an instruction current calculating section and 28 is a final steering reaction force calculating section.
The steering wheel 1 is a device that is handled by a driver. That is, when steering wheel 1 is handed by the driver, a torque sensor 2 a installed in steering reaction force actuator 2 detects a steering torque “TH” and at the same time, an encoder 2 b in the actuator 2 detects a steering angle “θH” by which steering wheel 1 has been steered by the driver.
Into steering motor drive section 7, there are inputted, in addition to information signals on the above-mentioned steering torque “TH” and steering angle “θH”, information signals on a yaw rate “y” of the vehicle detected by a yaw rate gyro or the like, a lateral acceleration “ÿ” of the vehicle detected by a lateral acceleration sensor or the like, and other known information such as a vehicle speed “Vs” and the like. Based on these information signals inputted, steering motor drive section 7 calculates an instruction current “i” which is applied to steering motor 9. As shown, the instruction current “i” is applied to road surface disturbance estimation section 14 also.
Output rotation of steering motor 9 is transmitted to steering gear unit 10, which is of a rack-and-pinion type, and thus, steered road wheels (not shown) are actuated by steering gear unit 10 through tie rods 11 a and 11 b.
The encoder 12 is arranged concentric with an output shaft of steering motor 9 to monitor or detect a rotation angle “θ” of the output shaft of steering motor 9. An information signal on rotation angle “θ” is fed back to steering motor drive section 7 to force the section 7 to carry out a servo control on the steered angle. The information signal on the rotation angle “θ” is fed to road surface disturbance estimation section 14 also.
That is, into road surface disturbance estimation section 14, there are inputted the information signal on the instruction current “i” applied to the steering motor 9 and that on the rotation angle “θ” of the output shaft of steering motor 9. Based on these information signals “i” and “θ”, the road surface disturbance estimation section 14 calculates an estimated disturbance torque “{circumflex over (T)}d” which would be caused by disturbance of road surface. The road surface disturbance estimation section 14 comprises generally a first block 15 into which the information signal “i” is inputted and a second block 16 into which the information signal “θ” is inputted.
As will be described hereinafter, by first block 15, a torque “t1” that should be generated is estimated. For this estimation, the following equation is employed: t 1 = K T ω 2 s 2 + 2 ξω   s + ω 2 ( 1 )
Figure US06751539-20040615-M00001
While, by second block 16, a torque “t2” that should be instructed is estimated. For this estimation, the following equation is employed: t 2 = J   ω 2 s 2 s 2 + 2 ξω   s + ω 2 ( 2 )
Figure US06751539-20040615-M00002
Into the second steering reaction force calculating section 21, there are inputted information signals on a vehicle running condition, that is, on steering torque “TH”, steering angle “θH”, yaw rate “y” of the vehicle, lateral acceleration “ÿ” of the vehicle, vehicle speed “Vs” and rotation angle “θ”. Based on these information signals, the second steering reaction force calculating section 21 calculates a steering reaction force “T2” which would be transmitted to the driver through the steering wheel 1.
In the second steering reaction force calculating section 18, a suitable gain is applied to the estimated disturbance torque “{circumflex over (T)}d” to calculate a steering reaction force “T1” which would be caused by the disturbance of road surface.
In the final steering reaction force calculating section 28, a subtraction “T2−T1” is carried out to obtain a final steering reaction force (T2−T1).
In the instruction current calculating section 22, the final steering reaction force (T2−T1) is divided by a torque constant “KTH” of steering reaction force actuator 2 to obtain an instruction current “iH” which is fed to the actuator 2.
In the following, operation of the vehicle steering control system 100 will be described with the aid of FIGS. 2, 3 and 4.
Estimation of Torque caused by Disturbance
FIG. 2 is a block diagram schematically showing the steering motor 9 based on an equation of motion of the motor 9. As shown, by multiplying the instruction current “i” by a torque constant “KT”, a torque “T” is obtained, and by dividing the torque “T” by an inertia “J” of motor 9, a rotation speed “{umlaut over (θ)}” of motor 9 is obtained. By differentiating the rotation speed “{umlaut over (θ)}” by time twice, a rotation angle “θ” of the output shaft of the motor 9 is obtained.
In case wherein there is a disturbance of road surface, the steering motor 9 can be schematically shown by FIG. 3 in which a disturbance torque “Td” is led to a middle of the block diagram of FIG. 2. Due to presence of the disturbance torque “Td”, it tends to occur that steering motor 9 exhibits excess or deficiency of output upon receiving the instruction current “i”. In general, in controlling steering motor 9, instruction and output of the motor 9 are evenly carried out by feeding back the rotation angle “θ” to the control.
FIG. 4 is a block diagram showing both steering motor 9 and road surface disturbance estimation section 14. As will be described in the following, in this case, by treating both the information on instruction current “i” and the information on the rotation angle “θ”, the disturbance torque “Td” is estimated. That is, the instruction current “i” led to steering motor 9 is fed to the first block 15. With this, the first block 15 estimates a torque “t1” in the form of transfer function, that should be generated. While, the information on rotation angle “θ” is led to the second block 16. With this, the second block 16 estimates a torque “t2” that would be instructed. By calculating a difference between the generated torque and the instructed torque, the estimated disturbance torque “{circumflex over (T)}d” is obtained.
Steering Reaction Force to be Added
During cruising of the vehicle, in the first steering reaction force calculating section 18 (see FIG. 1), a suitable gain “G” is kept applied to the estimated disturbance torque “{circumflex over (T)}d” to calculate a steering reaction force “T1” which would be caused by a disturbance of road surface. While, in the second steering reaction force calculating section 22, a steering reaction force “T2” is calculated based on the vehicle running condition. And at the final steering reaction force calculating section 28, a subtraction “T2−T1” is carried out to obtain a final steering reaction force (T2−T1). In the instruction current calculating section 22, the final steering reaction force (T2−T1) is divided by a torque constant “KTH” of steering reaction force actuator 2 to obtain an instruction current “iH” which is fed to the actuator 2.
In the following, advantageous matters obtained by the above-mentioned first embodiment 100 will be described.
Based on the input and output of the steering motor 9, the disturbance torque “Td” caused by a disturbance of road surface is estimated, and based on the estimated disturbance torque “Td”, the steering reaction force “T1” that is to be applied to the steering wheel 1 is calculated. Thus, information on roughness of road surface, that is of a degree of failing to induce a marked behavior of an associated motor vehicle, can be precisely transmitted to a driver without usage of an additional road surface sensor. That is, in the first embodiment 100, the estimation of disturbance of road surface is made by only the encoder 12 that is needed for controlling the steering motor 9. Accordingly, lowering in rigidity and that in reliability of the vehicle steering control system can be avoided.
The steering reaction force calculating part of the system 100 comprises the first steering reaction force calculating section 18 that, based on the estimated disturbance torque “{circumflex over (T)}d” from road surface disturbance estimation section 14, calculates the steering reaction force “T1” which would be caused by the disturbance of road surface, the second steering reaction force calculating section 21 that, based on various information on a marked behavior of the vehicle, calculates the steering reaction force “T2” which should be transmitted to the driver and the final steering reaction force calculating section 28 that, based on both the calculated two reaction forces “T1” and “T2”, calculates the final steering reaction force (T2−T1). That is, the final steering reaction force (T2−T1) thus calculated reflects both a reaction force based on the marked behavior of the vehicle and that based on the road surface disturbance “Td”, and thus, a precise steering reaction force can be transmitted to the driver.
Referring to FIG. 5, there is schematically shown the concept of a second embodiment 200 of the present invention.
As shown in the drawing, the second embodiment 200 is substantially the same as the above-mentioned first embodiment 100 except that in the second embodiment 200, the information on rotation angle “θ” of the output shaft of steering motor 9 is 10 treated by a first order lag filter 27 before being led into second block 16 of road surface disturbance estimation section 14. That is, due to treatment by the filter 27, information signal “θ” is changed to an information signal “θ′”, as shown.
In the filter 27, equation “a/(s+a)” is employed wherein “a” is a filter constant.
Operation of the second embodiment 200 will be described.
In a very early period of the steering action made by the driver, steering motor 9 produces an information representing the rotation angle “θ”. However, the behavior of the vehicle caused by the steering action occurs somewhat later, so that the vehicle steering control system of the above-mentioned first embodiment 100 may fail to calculate the steering reaction force based on the vehicle running condition and the result provided by road surface disturbance estimation section 14. Of course, in this case, satisfied information is not transmitted to the vehicle driver.
In case of the second embodiment 200, usage of first order lag filter 27 enables a delayed input of information on rotation angle “θ” into second block 16 of road surface disturbance estimation section 14. That is, in the second embodiment 200, in the early period of the steering action, the disturbance caused by the roughness of road surface is estimated relatively large. However, practically, the vehicle driver can feel a much actual steering reaction force, and thus, the steerability of the vehicle is improved.
Referring to FIG. 6, there is schematically shown the concept of a third embodiment 300 of the present invention.
As shown in the drawing, the third embodiment 300 is substantially the same as the above-mentioned first embodiment 100 except that in the third embodiment 300, the estimated disturbance torque “{circumflex over (T)}d” is treated by a second order lag filter 29 before being led into first steering reaction force calculating section 18 (see FIG. 1). That is, due to treatment by the filter 29, information “{circumflex over (T)}d” is changed to an information “{circumflex over (T)}d′”, as shown.
By the filter 29, the following equation is employed to derive the information “{circumflex over (T)}d′”: T ^   d ′ = ω 0 2 s 2 + 2 ξ 0 ω 0   s + ω 0 2 ( 3 )
Figure US06751539-20040615-M00003
In the third embodiment 300, by employing secondary filter 29, the frequency characteristic of the estimated disturbance torque can be suitably controlled. Specifically, in a high frequency zone, the gain of the estimated disturbance torque becomes small. Thus, when the vehicle steering control system 300 is practically used, an unnecessary marked vibration of a steering wheel, which would be generated when the vehicle is running on a bad road, is reduced. That is, the driver can receive only the information which is actually needed by the steering control.
The entire contents of Japanese Patent Application 2001-281362 filed Sep. 17, 2001 are incorporated herein by reference.
Although the invention has been described above with reference to the embodiments of the invention, the invention is not limited to such embodiments as described above. Various modifications and variations of such embodiments may be carried out by those skilled in the art, in light of the above description.

Claims (9)

What is claimed is:
1. A vehicle steering control system for use with a steering mechanism of steer-by-wire type, the steering mechanism including a first steering unit that is handed by a driver and a second steering unit that steers steered road wheels with the aid of a steering actuator, the first and second steering units being mechanically unconnected,
the vehicle steering control system comprising:
a steering reaction force actuator that generates a steering reaction force that is to be applied to the first steering unit in accordance with a steered movement of the steered road wheels;
an input detecting section that detects an input applied to the steering actuator;
an output detecting section that detects an output issued from the steering actuator;
a road surface disturbance estimating section that estimates a disturbance of road surface based on both the detected input and output of the steering actuator;
a steering reaction force calculating section that, based on the estimated disturbance of road surface, calculates a steering reaction force which is to be applied to the first steering unit; and
a steering reaction force control section that instructs the steering reaction force actuator to generate a steering reaction force in accordance with the calculated steering reaction force.
2. A vehicle steering control system as claimed in claim 1, in which the steering reaction force calculating section comprises:
a first steering reaction force calculating part that calculates a first steering reaction force based on the estimated disturbance of road surface;
a second steering reaction force calculating part that calculates a second steering reaction force based on a behavior of an associated motor vehicle; and
a third steering reaction force calculating part that, by subtracting the calculated first steering reaction force from the calculated second steering reaction force, calculates a final steering reaction force that is actually applied to the steering reaction force actuator.
3. A vehicle steering control system as claimed in claim 1, further comprising a filter through which a signal of the output from the output detecting section is led into the road surface disturbance estimating section.
4. A vehicle steering control system as claimed in claim 3, in which the filter is a first order lag filter.
5. A vehicle steering control system as claimed in claim 1, further comprising a filter through which a signal of the estimated disturbance of road surface from the road surface disturbance estimating section is led into the steering reaction force calculating section.
6. A vehicle steering control system as claimed in claim 5, in which the filter is a second order lag filter.
7. A vehicle steering control system as claimed in claim 1, in which the road surface disturbance estimating section comprises:
a first block that processes the detected input to estimate a first torque in the form of transfer function;
a second block that processes the detected output to estimate a second torque in the form of transfer function; and
a calculating section that calculates a difference between the estimated first torque and the estimated second torque.
8. A vehicle steering control system for use with a steering mechanism of steer-by-wire type, the steering mechanism including a first steering unit that is handed by a driver and a second steering unit that steers steered road wheels with the aid of a steering actuator, the first and second steering units being mechanically unconnected,
the vehicle steering control system comprising:
a steering reaction force generating means that generates a steering reaction force that is to be applied to the first steering unit in accordance with a steered movement of the steered road wheels;
an input detecting means that detects an input applied to the steering actuator;
an output detecting means that detects an output issued from the steering actuator;
a road surface disturbance estimating means that estimates a disturbance of road surface based on both the detected input and output of the steering actuator;
a steering reaction force calculating means that, based on the estimated disturbance of road surface, calculates a steering reaction force which is to be applied to the first steering unit; and
a steering reaction force control means that instructs the steering reaction force actuator to generate a steering reaction force in accordance with the calculated steering reaction force.
9. In a vehicle steering control system for use with a steering mechanism of steer-by-wire type, the steering mechanism including a first steering unit that is handed by a driver and a second steering unit that steers steered road wheels without a direct aid of the first steering unit, a steering actuator that actuates the second steering unit and a steering reaction force actuator that applies a steering reaction force to the first steering unit in accordance with a steered movement of the steered road wheels,
a method of controlling the vehicle steering control system comprising:
detecting an input applied to the steering actuator;
detecting an output issued from the steering actuator;
estimating a disturbance of road surface based on both the detected input and output of the steering actuator;
calculating, based on the estimated disturbance of road surface, a steering reaction force which is to be applied to the first steering unit; and
instructing the steering reaction force actuator to generate a steering reaction force in accordance with the calculated steering reaction force.
US10/241,781 2001-09-17 2002-09-12 Vehicle steering control system Expired - Lifetime US6751539B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2001-281362 2001-09-17
JP2001281362A JP3705173B2 (en) 2001-09-17 2001-09-17 Vehicle steering control device

Publications (2)

Publication Number Publication Date
US20030055545A1 US20030055545A1 (en) 2003-03-20
US6751539B2 true US6751539B2 (en) 2004-06-15

Family

ID=19105195

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/241,781 Expired - Lifetime US6751539B2 (en) 2001-09-17 2002-09-12 Vehicle steering control system

Country Status (3)

Country Link
US (1) US6751539B2 (en)
JP (1) JP3705173B2 (en)
DE (1) DE10241695B4 (en)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040245041A1 (en) * 2000-07-21 2004-12-09 Toshihiro Fukuda Motor-operated power steering apparatus
US20050082106A1 (en) * 2003-10-16 2005-04-21 Visteon Global Technologies, Inc. End of travel system and method for steer by wire systems
KR100543245B1 (en) * 2003-03-17 2006-01-20 현대모비스 주식회사 apparatus for detecting absolute position of electromotive steering wheel
US20060017413A1 (en) * 2002-09-19 2006-01-26 Nsk Ltd. Control device for motorized power steering device
US20060037806A1 (en) * 2004-05-27 2006-02-23 Nissan Motor Co., Ltd. Vehicle steering apparatus and method
US20070219691A1 (en) * 2006-03-15 2007-09-20 Mazda Motor Corporation Steering apparatus for vehicle
US20080164087A1 (en) * 2006-12-28 2008-07-10 Jtekt Corporation Steering device for vehicle
US20080206970A1 (en) * 2005-04-10 2008-08-28 Franz Hugo Production Of Polycrystalline Silicon
US20080294355A1 (en) * 2004-03-23 2008-11-27 Thomas Berthold Tire Lateral Force Determination in Electrical Steering Systems
KR100878687B1 (en) 2007-09-18 2009-01-13 위아 주식회사 Apparatus for measuring vertical displacement for use in vehicle road load test
US20120253603A1 (en) * 2007-04-02 2012-10-04 Jtekt Corporation Vehicle steering apparatus
US11279401B2 (en) * 2019-03-07 2022-03-22 Toyota Jidosha Kabushiki Kaisha Vehicle control system
US11685427B2 (en) 2021-04-12 2023-06-27 Toyota Material Handling, Inc. Electric actuator steering system for forklifts
US12024248B2 (en) 2020-02-07 2024-07-02 Nsk Ltd. Vehicle steering device

Families Citing this family (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7233850B2 (en) * 2002-10-31 2007-06-19 Koyo Seiko Co., Ltd. Vehicle steering apparatus
GB2400358A (en) * 2003-04-09 2004-10-13 Trw Ltd Steering rack disturbance force rejection
JP4466066B2 (en) * 2003-08-28 2010-05-26 日産自動車株式会社 Vehicle steering control device
JP4231416B2 (en) * 2004-01-07 2009-02-25 トヨタ自動車株式会社 Vehicle steering device
US7032705B2 (en) * 2004-02-27 2006-04-25 Visteon Global Technologies, Inc. Oversteering/understeering compensation with active front steering using steer by wire technology
JP2006130940A (en) * 2004-11-02 2006-05-25 Toyoda Mach Works Ltd Steer-by-wire system
JP4581651B2 (en) * 2004-11-29 2010-11-17 日産自動車株式会社 Vehicle steering system
JP4661210B2 (en) * 2004-12-24 2011-03-30 日産自動車株式会社 Vehicle steering control device
JP4727461B2 (en) * 2005-04-19 2011-07-20 本田技研工業株式会社 Vehicle steering system
JP4906333B2 (en) * 2005-12-08 2012-03-28 トヨタ自動車株式会社 Vehicle steering device
JP4984625B2 (en) * 2006-04-24 2012-07-25 トヨタ自動車株式会社 Vehicle steering device
JP5093552B2 (en) * 2006-05-09 2012-12-12 株式会社ジェイテクト Vehicle steering system
JP4821502B2 (en) * 2006-08-21 2011-11-24 トヨタ自動車株式会社 Vehicle steering device
JP4362137B2 (en) * 2007-02-28 2009-11-11 三菱電機株式会社 Vehicle steering system
US8706355B2 (en) * 2009-07-29 2014-04-22 Toyota Jidosha Kabushiki Kaisha Steering control system
US8788149B2 (en) * 2010-08-05 2014-07-22 Toyota Jidosha Kabushiki Kaisha Steering control device
JP5772686B2 (en) * 2012-04-04 2015-09-02 トヨタ自動車株式会社 Electric power steering device
US9569954B2 (en) * 2012-12-13 2017-02-14 Brian L. Ganz Method and system for controlling a vehicle with a smartphone
EP2944545B1 (en) * 2013-01-11 2017-11-01 Nissan Motor Co., Ltd Steering control device
JP6314552B2 (en) * 2014-03-07 2018-04-25 株式会社ジェイテクト Electric power steering device
JP5844861B2 (en) * 2014-09-01 2016-01-20 Ntn株式会社 Steer-by-wire steering reaction force control device
EP3178724B1 (en) * 2015-12-08 2018-10-24 Volvo Car Corporation Vehicle steering arrangement, autonomous vehicle steering arrangement, a vehicle, and a method of steering a vehicle
US10501112B2 (en) * 2016-11-14 2019-12-10 Ford Global Technologies, Llc Steering system with active compensation for road disturbances
US10676129B2 (en) * 2018-06-25 2020-06-09 Steering Solutions Ip Holding Corporation Driver notification using handwheel actuators in steer-by-wire systems
JP7124772B2 (en) * 2019-03-12 2022-08-24 トヨタ自動車株式会社 vehicle steering system
CN110606121B (en) * 2019-08-28 2021-02-19 中国第一汽车股份有限公司 Drive-by-wire steering road feel simulation control method

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5406474A (en) * 1990-07-16 1995-04-11 The Foxboro Company Self-tuning controller
JPH1178947A (en) 1997-09-16 1999-03-23 Koyo Seiko Co Ltd Steering device for vehicle
US5908457A (en) * 1995-11-24 1999-06-01 Koyo Seiko Co., Ltd. Automobile steering system including reaction feedback to operator
JP2000128002A (en) 1998-10-26 2000-05-09 Toyota Motor Corp Steering control device
US6097286A (en) * 1997-09-30 2000-08-01 Reliance Electric Technologies, Llc Steer by wire system with feedback
US6176341B1 (en) * 1999-02-01 2001-01-23 Delphi Technologies, Inc. Vehicle steering system having master/slave configuration and method therefor
US6219604B1 (en) * 1998-12-29 2001-04-17 Robert Bosch Gmbh Steer-by-wire steering system for motorized vehicles
US6505703B2 (en) * 2001-03-14 2003-01-14 Visteon Global Technologies, Inc. Vehicle steering system control

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3191520B2 (en) * 1993-09-14 2001-07-23 オムロン株式会社 Electric power steering device
JP3298006B2 (en) * 1998-12-24 2002-07-02 日本精工株式会社 Control device for electric power steering device
DE19912169A1 (en) * 1998-12-29 2000-07-06 Bosch Gmbh Robert Steer-by-wire steering system for vehicles has electronic steering regulator connected to steering control devices that modifies driver's steering demand depending on dynamic parameters
JP3176899B2 (en) * 1999-06-21 2001-06-18 本田技研工業株式会社 Vehicle steering system

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5406474A (en) * 1990-07-16 1995-04-11 The Foxboro Company Self-tuning controller
US5908457A (en) * 1995-11-24 1999-06-01 Koyo Seiko Co., Ltd. Automobile steering system including reaction feedback to operator
JPH1178947A (en) 1997-09-16 1999-03-23 Koyo Seiko Co Ltd Steering device for vehicle
US6097286A (en) * 1997-09-30 2000-08-01 Reliance Electric Technologies, Llc Steer by wire system with feedback
JP2000128002A (en) 1998-10-26 2000-05-09 Toyota Motor Corp Steering control device
US6219604B1 (en) * 1998-12-29 2001-04-17 Robert Bosch Gmbh Steer-by-wire steering system for motorized vehicles
US6176341B1 (en) * 1999-02-01 2001-01-23 Delphi Technologies, Inc. Vehicle steering system having master/slave configuration and method therefor
US6505703B2 (en) * 2001-03-14 2003-01-14 Visteon Global Technologies, Inc. Vehicle steering system control

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040245041A1 (en) * 2000-07-21 2004-12-09 Toshihiro Fukuda Motor-operated power steering apparatus
US7219761B2 (en) 2000-07-21 2007-05-22 Nsk Ltd. Motor-operated power steering apparatus
US20060017413A1 (en) * 2002-09-19 2006-01-26 Nsk Ltd. Control device for motorized power steering device
US7242161B2 (en) * 2002-09-19 2007-07-10 Nsk, Ltd. Control device for motorized power steering device
KR100543245B1 (en) * 2003-03-17 2006-01-20 현대모비스 주식회사 apparatus for detecting absolute position of electromotive steering wheel
US6926112B2 (en) * 2003-10-16 2005-08-09 Visteon Global Technologies, Inc. End of travel system and method for steer by wire systems
US20050082106A1 (en) * 2003-10-16 2005-04-21 Visteon Global Technologies, Inc. End of travel system and method for steer by wire systems
US20080294355A1 (en) * 2004-03-23 2008-11-27 Thomas Berthold Tire Lateral Force Determination in Electrical Steering Systems
US20060037806A1 (en) * 2004-05-27 2006-02-23 Nissan Motor Co., Ltd. Vehicle steering apparatus and method
US7246679B2 (en) * 2004-05-27 2007-07-24 Nissan Motor Co., Ltd. Vehicle steering apparatus and method
US20080206970A1 (en) * 2005-04-10 2008-08-28 Franz Hugo Production Of Polycrystalline Silicon
US7520365B2 (en) * 2006-03-15 2009-04-21 Mazda Motor Corporation Steering apparatus for vehicle
US20070219691A1 (en) * 2006-03-15 2007-09-20 Mazda Motor Corporation Steering apparatus for vehicle
US20080164087A1 (en) * 2006-12-28 2008-07-10 Jtekt Corporation Steering device for vehicle
US8177019B2 (en) * 2006-12-28 2012-05-15 Jtekt Corporation Steering device for vehicle
US20120253603A1 (en) * 2007-04-02 2012-10-04 Jtekt Corporation Vehicle steering apparatus
US8744687B2 (en) * 2007-04-02 2014-06-03 Jtekt Corporation Vehicle steering apparatus
KR100878687B1 (en) 2007-09-18 2009-01-13 위아 주식회사 Apparatus for measuring vertical displacement for use in vehicle road load test
US11279401B2 (en) * 2019-03-07 2022-03-22 Toyota Jidosha Kabushiki Kaisha Vehicle control system
US12024248B2 (en) 2020-02-07 2024-07-02 Nsk Ltd. Vehicle steering device
US11685427B2 (en) 2021-04-12 2023-06-27 Toyota Material Handling, Inc. Electric actuator steering system for forklifts

Also Published As

Publication number Publication date
DE10241695B4 (en) 2007-06-06
US20030055545A1 (en) 2003-03-20
JP3705173B2 (en) 2005-10-12
DE10241695A1 (en) 2003-05-15
JP2003081111A (en) 2003-03-19

Similar Documents

Publication Publication Date Title
US6751539B2 (en) Vehicle steering control system
US7676309B2 (en) Motor-driven power steering apparatus
EP1541445B1 (en) Control device for motorized power steering device
EP2492168B1 (en) Electric power steering device for vehicle
JP3681324B2 (en) Torque detection device and electric power steering device
US8738229B2 (en) Electric power steering device and method for controlling the same
US6112845A (en) Reactive steering control system
US20080185212A1 (en) Vehicle steering system, vehicle including the same and method for turning wheel of vehicle
EP3626580B1 (en) Motor control device and motor control method
JP2007269140A (en) Control device of electric power steering system
EP3699062B1 (en) Steering system
US20190256126A1 (en) Quadrant based friction compensation for tire load estimation in steering systems
JP3649007B2 (en) Vehicle reverse determination method and vehicle control apparatus
JP4186913B2 (en) Steering reaction control device for steer-by-wire steering device
JP7256958B2 (en) electric power steering device
US6148951A (en) Reactive steering control system
CN111591341B (en) Electric power steering apparatus
KR100971284B1 (en) Electric current direct measurement Steer-By-Wire steering control device
US6619422B2 (en) Steering unit and internal drag calculation apparatus used therein
JP3714269B2 (en) Automatic steering device
JP4545054B2 (en) Electric power steering device
JP2009047542A (en) Torque detection device and steering unit
JP2004168150A (en) Electronic steering device
JP4000782B2 (en) Electric power steering device
JP3555126B2 (en) Steering control device

Legal Events

Date Code Title Description
AS Assignment

Owner name: NISSAN MOTOR CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:UENUMA, KENYA;MOURI, HIROSHI;REEL/FRAME:013286/0716

Effective date: 20020820

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

STCF Information on status: patent grant

Free format text: PATENTED CASE

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12